This investigation on the composition of fatty acids of hempseed through gas -chromatography analysis found the follwing results. Myristic acid and other ten materials were detected. And there was mainly composed of myristic acid 29.4%, palmitoleic acid 16.2%, linoleic acid 14.9%, oleic acid 12.4%. It also showed that heptadecanoic acid 10.8%, erucic acid 0.5%, docosahexaenoic acid 0.3% and essential fatty acid were contained 17.9% between them. As stearic acid, docosahexaenoic acid, linoleic acid and arachidonic acid made lower cholesterol level in body, they will help prevention of senile disease with the oil of hemp seed.